(A) Generation of novel haplotype diversity from secondary mutations during a selective sweep. At t = 0 a beneficial mutation establishes and the frequency, x₀, of its underlying haplotype (blue) rises. After some time, a neutral mutation occurs in an individual carrying the beneficial mutation, creating a new adaptive haplotype variant (red) that itself increases in frequency, x₁. This happens repeatedly, giving rise to a range of low-frequency haplotypes that all descended from the initial founding haplotype. Sweep parameters are s = 0.03 and u = 0.004, and seeding times of new variants are given by Equation 4. (B) The distribution of seeding times for different i according to Equation 3.